Peptidomics characteristics of pediatric sepsis.

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, has an approximately 25% in-hospital mortality rate. Identifying early biomarkers of pediatric sepsis is crucial for improving outcomes. This study explored the differential expression of peptides in patients with sepsis compared to healthy controls and those with common infections using plasma peptidomic analysis. Blood samples were collected from 10 pediatric patients with sepsis admitted to Hunan Children's Hospital in 2021, along with 20 age- and sex-matched healthy controls and five children with common infections. Differential peptide precursor proteins underwent gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses and protein-protein interaction analysis using the STRING database. Intotal, 3149 endogenous peptides corresponding to 480 precursor proteins were identified. Compared to the healthy group, the sepsis group exhibited 1113 differentially expressed peptides, with 880 upregulated and 233 downregulated. Compared with the common infection group, the sepsis group showed 181 upregulated and 86 downregulated peptides. These differences were primarily in the humoral immune response and complement and coagulation cascades. This study identified specific alterations in peptide expression in the plasma of patients with sepsis, most notably in peptides related to SAA1, complement C3, hemoglobin, and haptoglobin. These peptides are involved in the acute inflammatory response, complement system, and free hemoglobin pathways, indicating their crucial roles in sepsis pathology. These findings provide new insights into the mechanisms of sepsis and suggest potential applications for these peptides in sepsis diagnosis and treatment, to enhance early diagnosis and therapeutic outcomes.